While plenty of new faces are arriving at the Philly elementary school, Abbott fans can rest assured that some traditions are back. After having a midseason start last year, the show is back to a 22-episode season, which means holiday episodes are coming.

Abbott Elementary” star and creator, Quinta Brunson, and “It’s Always Sunny in Philadelphia” star and co-creator. Rob McElhenney, both shared news they’re collaborating on a crossover episode on social media.

The ABC series will crossover with FX’s It’s Always Sunny in Philadelphia for Season 4. Rob McElhenney, Danny Devito and Charlie Day will appear in the episode, as confirmed by a photo posted on social media Thursday.